1. Technical Field
The present invention relates to an optical scanner, an actuator, an image display device, and a head-mounted display.
2. Related Art
An optical scanner which is used in a projector, a head-mounted display, and the like and which two-dimensionally scans light is known (for example, see JP-A-2003-207737).
An optical scanner described in JP-A-2003-207737 includes an outer frame (fixing portion), an inner frame (frame body portion) which is provided at an inner side of the outer frame, a pair of second elastic beams (second shaft portions) which rotatably supports the inner frame against the outer frame, a mirror portion (movable portion) which is provided at an inner side of the inner frame, and a pair of first elastic beams (first shaft portions) which rotatably supports the mirror portion against the inner frame.
In the optical scanner, the inner frame is made to rotate with respect to the outer frame while torsionally deforming the second elastic beams, and the mirror portion is made to rotate with respect to the inner frame while torsionally deforming the first elastic beams. According to this, two-dimensional scanning with light reflected by the mirror portion is carried out.
In addition, in the optical scanner described in JP-A-2003-207737, a piezoresistor is disposed over the first elastic beams between the mirror portion and the inner frame. According to this, rotation of the mirror portion due to twist deformation of the first elastic beams can be detected based on variation in a resistance value of the piezoresistor.
In the optical scanner described in JP-A-2003-207737, since the piezoresistor is provided over the first elastic beams between the mirror portion and the inner frame, it is necessary to dispose an interconnection for supplying power to the piezoresistor or an interconnection for taking-out a detection signal of the piezoresistor throughout the entire region over the second elastic beams between the inner frame and the outer frame.
As described above, when the interconnection is formed over the entire region over the second elastic beams, the interconnection passes over a portion at which an amount of deformation due to the torsion of the second elastic beams becomes the maximum, the interconnection receives repetitive stress due to the torsional deformation of the elastic beams, and thus there is a problem that the interconnection may be disconnected.